/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.consensus.iot.util;

import org.apache.iotdb.consensus.common.DataSet;
import org.apache.iotdb.consensus.common.request.IndexedConsensusRequest;
import org.apache.iotdb.consensus.iot.wal.ConsensusReqReader;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class FakeConsensusReqReader implements ConsensusReqReader, DataSet {

    private final RequestSets requestSets;

    public FakeConsensusReqReader(RequestSets requestSets) {
        this.requestSets = requestSets;
    }

    @Override
    public void setSafelyDeletedSearchIndex(long safelyDeletedSearchIndex) {
    }

    @Override
    public ReqIterator getReqIterator(long startIndex) {
        return new FakeConsensusReqIterator(startIndex);
    }

    @Override
    public long getCurrentSearchIndex() {
        return requestSets.getLocalRequestNumber();
    }

    @Override
    public long getTotalSize() {
        return 0;
    }

    private class FakeConsensusReqIterator implements ConsensusReqReader.ReqIterator {
        private long nextSearchIndex;

        public FakeConsensusReqIterator(long startIndex) {
            this.nextSearchIndex = startIndex;
        }

        @Override
        public boolean hasNext() {
            return true;
        }

        @Override
        public IndexedConsensusRequest next() {
            synchronized (requestSets) {
                for (IndexedConsensusRequest indexedConsensusRequest : requestSets.getRequestSet()) {
                    if (indexedConsensusRequest.getSearchIndex() == nextSearchIndex) {
                        nextSearchIndex++;
                        return indexedConsensusRequest;
                    }
                }
                return null;
            }
        }

        @Override
        public void waitForNextReady() throws InterruptedException {
            while (!hasNext()) {
                requestSets.waitForNextReady();
            }
        }

        @Override
        public void waitForNextReady(long time, TimeUnit unit)
                throws InterruptedException, TimeoutException {
            while (!hasNext()) {
                requestSets.waitForNextReady(time, unit);
            }
        }

        @Override
        public void skipTo(long targetIndex) {
            nextSearchIndex = targetIndex;
        }
    }
}
